package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * 代金券订单服务
 *
 * @author zhanhong
 * @date 2023/01/31
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Autowired
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private RedissonClient redissonClient;
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    //加载脚本
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    /**
     * 创建一个线程池
     */
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    /**
     * 在方法上加该注解会在项目启动的时候执行该方法，
     * 也可以理解为在spring容器初始化的时候执行该方法。
     */
    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VocherOrderHandler());
    }

    private class VocherOrderHandler implements Runnable {
        /**
         * 队列名称
         */
        String queueName = "stream.orders";

        @Override
        public void run() {
            while (true) {
                try {
                    //1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STEAMS stream.order
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //2.判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        //2.1 如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    //解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //3.获取成功 创建订单
                    handleVoucherOrder(voucherOrder);
                    //ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    //1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 STEAMS stream.order 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2.判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        //2.1 如果获取失败，说明pending-list没有消息，
                        break;
                    }
                    //解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //3.获取成功 创建订单
                    handleVoucherOrder(voucherOrder);
                    //ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list异常", e);
                    try {
                        Thread.sleep(20000);
                    } catch (InterruptedException interruptedException) {
                        interruptedException.printStackTrace();
                    }
                }
            }
        }
    }



  /*  //创建一个阻塞队列
    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024*1024);
    //创建线程任务 用来进行异步操作
    private class VocherOrderHandler implements Runnable{

        @Override
        public void run() {
            while(true){
                try {
                    //1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder(voucherOrder);

                } catch (Exception e) {
                    log.error("处理订单异常",e);

                }
            }
        }
    }*/

    //创建订单
    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1.获取用户
        Long userId = voucherOrder.getUserId();
        //2.创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //3.获取锁
        boolean isLock = lock.tryLock();
        //4.判断是否获取锁成功
        if (!isLock) {
            //获取锁失败，返回错误并重试
            log.error("不允许重复下单");
            return;
        }
        try {
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            //5.释放锁
            lock.unlock();
        }

    }

    private IVoucherOrderService proxy;

    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );
        //2.判断结果是为0
        int r = result.intValue();
        if (r != 0) {
            //2.1 不为0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //3.获取代理对象（事务）
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        //3.返回订单id
        return Result.ok(0);
    }

    /**
     * 创建凭证秩序
     *
     * @param voucherOrder 券订单
     *//*【基于阻塞队列】
    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString()
        );
        //2.判断结果是为0
        int r = result.intValue();
        if(r != 0){
            //2.1 不为0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //2.2 为0 有购买资格，把下单信息保存到阻塞队列中
        VoucherOrder voucherOrder = new VoucherOrder();
        //2.3 订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //2.4 用户id
        voucherOrder.setUserId(userId);
        //2.5 代金券id
        voucherOrder.setVoucherId(voucherId);
        //2.6 放入阻塞队列
        orderTasks.add(voucherOrder);

        //3.获取代理对象（事务）
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        //3.返回订单id
        return Result.ok(0);
    }
*/
    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //5.一人一单
        Long userid = UserHolder.getUser().getId();
        //创建锁对象
        RLock redisLock = redissonClient.getLock("lock:order:" + userid);
        //尝试获取锁
        boolean isLock = redisLock.tryLock();
        //判断
        if (!isLock) {
            //获取锁失败，直接返回或重试
            log.error("不允许重复下单");
        }

        try {
            //5.1 查询订单
            query().eq("user_id", userid).eq("voucher_id", voucherOrder.getVoucherId()).count();
            //5.2判断是否存在
            if (count() > 0) {
                //用户已经购买过了
                log.error("用户已经购买了一次");
            }
            //6. 扣减库存
            boolean success = seckillVoucherService.update()
                    .setSql("stock = stock - 1") //set stock = stock - 1
                    .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0) // where voucher_id = ? and stock = ?
                    .update();

            if (!success) {
                //扣减失败
                log.error("库存不足");
            }

            //7.创建订单
            save(voucherOrder);

        } finally {
            //释放锁
            redisLock.unlock();
        }


    }


    /* //秒杀优惠券
    @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())){
            //2.1 尚未开始
            return Result.fail("秒杀活动尚未开始");
        }
        //3.判断秒杀是否结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now()))
            //3.1 秒杀结束
            return Result.fail("秒杀活动已结束");
        //4.判断库存是否充足
        if (voucher.getStock() < 1){
            //4.1 库存不足
            return Result.fail("优惠券已经被抢光了");
        }
        return createVoucherOrder(voucherId);
    }
*/













    /*@Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //2.3 订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );
        //2.判断结果是为0
        int r = result.intValue();
        if(r != 0){
            //2.1 不为0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //2.2 为0 有购买资格，把下单信息保存到阻塞队列中
        VoucherOrder voucherOrder = new VoucherOrder();

        voucherOrder.setId(orderId);
        //2.4 用户id
        voucherOrder.setUserId(userId);
        //2.5 代金券id
        voucherOrder.setVoucherId(voucherId);
        //2.6 放入阻塞队列
        orderTasks.add(voucherOrder);

        //3.获取代理对象（事务）
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        //3.返回订单id
        return Result.ok(0);
    }*/

   /* @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString()
        );
        //2.判断结果是为0
        int r = result.intValue();
        if(r != 0){
            //2.1 不为0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //2.2 为0 有购买资格，把下单信息保存到阻塞队列中
        VoucherOrder voucherOrder = new VoucherOrder();
        //2.3 订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //2.4 用户id
        voucherOrder.setUserId(userId);
        //2.5 代金券id
        voucherOrder.setVoucherId(voucherId);
        //2.6 放入阻塞队列
        orderTasks.add(voucherOrder);

        //3.获取代理对象（事务）
         proxy = (IVoucherOrderService) AopContext.currentProxy();

        //3.返回订单id
        return Result.ok(0);
    }*/

    /*
    @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            //没开始
            return Result.fail("秒杀尚未开始！");
        }
        //3.判断秒杀是否结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            //已结束
            return Result.fail("秒杀已结束");
        }
        //4.判断库存是否充足
        if (voucher.getStock() < 1) {
            //库存不足
            return Result.fail("库存不足");
        }

        Long userId = UserHolder.getUser().getId();

        //【方式一】虚拟器内部的锁 各个进程的锁独立 没有处于同一个锁监视器下
//        synchronized (userId.toString()) {
//            //获取代理对象（事务）
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        }

        // 【方式二】分布式锁 所有的锁处于同一个监视器下
        //创建锁对象
        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        //判断是否获取锁成功
        Boolean isLock = lock.tryLock(1000);
        if (!isLock){
            //获取锁失败，返回错误信息
            return Result.fail("请不要重复下单");
        }
        try{
            //获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        }finally {
            //释放锁
            lock.unLock();
        }


    }*/


}

